I. Field of the Invention
This invention relates generally to surgical and diagnostic endoscopes and, more particularly, to an endoscope with a selectively deflectable tip portion to facilitate maneuvering or steering of the distal end thereof.
II. Discussion of the Prior Art
In performing a variety of surgical procedures without a major incision, a surgeon typically may use an endoscope having several lumens therewithin providing flush ports, suction ports, a passageway for routing a first optical fiber for illuminating and another for conveying the image and frequently, but not necessarily, a working lumen for allowing another instrument to be passed therethrough. A light source is usually placed at the proximal end of the illumination fiber to illuminate the internal area being operated upon. An optical image is transmitted back through the endoscope, via the image optical fibers, to aid the surgeon during the operation. Endoscopes having a rigid sheath are adapted to be maneuvered by the surgeon exterior of the patient to locate the distal end proximate the selected tissue. The distal end, then, is finely positioned to locate it adjacent the tissue to be examined or operated upon, at which point a surgical instrument disposed in the working lumen may be activated.
Various endoscopes are known in the art having steerable distal tips. Generally speaking, the maneuverability these endoscopes provide the surgeon with only a limited ability to conveniently maneuver the distal tip. Some instruments have a limited rotation angle which is less than 180 degrees. This limitation prevents access to a wall adjacent an opening through which the endoscope is inserted. Others have a radius of curvature which is fixed, thus restricting the accessibility of the distal tip to the tissue without significant efforts of the surgeon maneuvering of the endoscope exterior to the patient. Excessive maneuvering of the endoscope exterior of the patient is frustrating, time consuming, and inefficient to the surgeon performing a delicate operation.
U.S. Pat. No. 4,245,624, issued to Komiya, teaches a flexible tube section projecting out from the distal end of an endoscope. A wire is located exterior to the flexible portion and is bridged from the distal end of the endoscope to the end of the flexible portion. While providing the ability to steer the flexible end portion, this wire inhibits the maneuverability of the flexible portion in tight and delicate locations of the patient. Further, the length of the flexible portion is not selectable.
U.S. Pat. No. 4,586,923, issued to Gould et al., shows a catheter with a curving distal tip. The exterior sheath of the catheter is stiff, but an extending tip is flexible. A wire located within a lumen and connected to the flexible tip causes the tip to flex when retracted. The flexible portion of this catheter is a fixed length, thus defining a radius of curvature which may prove to be either too large or too small, depending on the operation being performed by the surgeon.
U.S. Pat. No. 4,960,41, issued to Buchbinder, teaches a steerable catheter substantially enclosed in a catheter shell. The flexible distal tip portion of the catheter is not adjustable in length, hence, the radius of curvature of the tip is not selectable. Rather, only the angle of deflection is selectable. The use of this instrument would be limited in some procedures where the radius and length of the flexible tip requires adaptation to a particular body cavity. Further, the desirable tip size typically would not be known until the tip is inserted into the patient proximate the desired tissue. Trial and error during surgery is time consuming and frustrating.
U.S. Pat. No. 4,898,577, issued to Badger et al., teaches a guiding catheter with a controllable distal tip having articulated sections. The deflection of the distal tip is not continuous, and the radius of curvature is not selectable. Hence, the maneuverability of the guiding catheter is somewhat limited for surgical procedures in a very small cavity.